Personally I've settled on the technique of partial tranny fluid replacement - draining however much comes out of the pan and refilling that same amount. Although this method doesn't completely replace the fluid, I believe it's effective when done along with every one or two oil changes. JMO, based on personal experience and lots of research.
This is my preferred method too. I've been doing it with my Wrangler for quite a while. Its ATX runs notoriously hot, especially when offroading. Sump temps of 200+ are not uncommon without an aftermarket cooler.
I stick one of these...
...down the dip stick tube and suck out some fluid, then refill.